The present disclosure relates to communication apparatuses and particularly relates to a technique in which when a destination communication apparatus causes an error requiring repair, the destination communication apparatus notifies a source communication apparatus of temporal inexecutability information.
For example, there is proposed, as a technique for data transmission using communication based on SIP (Session Initiation Protocol), a technique A in which if a data storage section, such as a memory, of a destination facsimile apparatus (an example of a communication apparatus) is short of available space when a source facsimile apparatus transmits transmission target data to the destination facsimile apparatus, the destination facsimile apparatus transmits to the source facsimile apparatus information indicating the shortage of available space and information indicating the time when it will be able to receive the data and the source facsimile apparatus then transmits the transmission target data with the advent of the time when the destination facsimile apparatus becomes able to receive the data.
There is also proposed a technique B in which when a source facsimile apparatus receives from a destination facsimile apparatus temporal inexecutability information indicating that the destination facsimile apparatus is temporarily unable to execute the connection processing required by a connection request from the source facsimile apparatus and containing a processing executable time when the destination facsimile apparatus will be able to execute the connection processing, the source facsimile apparatus disconnects communication for the connection request, postpones the retransmission of the connection request to the destination until the end of a waiting period based on the temporal inexecutability information, and, upon receipt of a state update indicating that the connection processing has become executable from the destination during the postponement of retransmission of the connection request for the waiting period, retransmits the connection request to the destination even before the end of the waiting period.